What is the treatment for Kawasaki disease in children?

Treatment of Kawasaki Disease in Children

The standard treatment for Kawasaki disease in children consists of intravenous immunoglobulin (IVIG) at 2 g/kg as a single infusion combined with high-dose aspirin (80-100 mg/kg/day divided into four doses), which should be administered within the first 10 days of illness onset to reduce the risk of coronary artery abnormalities. 1, 2

Initial Treatment Protocol

• IVIG should be administered at 2 g/kg as a single infusion as soon as the diagnosis is established, preferably within the first 10 days of illness and if possible within 7 days 1
• High-dose aspirin (80-100 mg/kg/day divided into four doses) should be given concurrently with IVIG until the patient is afebrile for at least 48 hours 1, 2
• After the fever resolves, transition to low-dose aspirin (3-5 mg/kg/day as a single daily dose) and continue until there is no evidence of coronary changes by 6-8 weeks after illness onset 1, 2
• For children who develop coronary abnormalities, aspirin may need to be continued indefinitely 1, 2

Management of IVIG-Resistant Disease

• Approximately 10-20% of patients develop recurrent or persistent fever at least 36 hours after IVIG infusion 2
• For IVIG-resistant cases, treatment options include:
  • A second dose of IVIG (2 g/kg as a single infusion) as the first option 1, 2
  • Corticosteroids may be considered in patients who remain febrile after the second dose of IVIG 1, 2
  • Other agents such as infliximab or methotrexate may be considered in refractory cases 2, 3

Aspirin Dosing Considerations

• While both high-dose and low-dose aspirin regimens are used in clinical practice, some evidence suggests high-dose aspirin may be associated with lower rates of IVIG resistance 4
• A meta-analysis comparing low-dose (3-5 mg/kg/day) with high-dose aspirin (≥30 mg/kg/day) found no significant differences in coronary artery lesion incidence, though there was a trend toward higher IVIG resistance with low-dose aspirin 5
• Ibuprofen should be avoided in children with coronary aneurysms taking aspirin for its antiplatelet effects, as it antagonizes aspirin's irreversible platelet inhibition 1

Monitoring and Long-term Management

• Echocardiography should be performed at diagnosis, 1-2 weeks after treatment, and 4-6 weeks after treatment to assess for coronary artery abnormalities 1, 2
• For patients with coronary artery abnormalities:
  • Small aneurysms: continue low-dose aspirin indefinitely 2
  • Moderate aneurysms (4-6 mm): aspirin plus a second antiplatelet agent 2
  • Giant aneurysms (≥8 mm): aspirin plus warfarin (target INR 2.0-3.0) or low-molecular-weight heparin 2

Important Caveats and Pitfalls

• Delayed treatment beyond 10 days significantly increases the risk of coronary artery abnormalities 1, 2
• Children taking aspirin should receive annual influenza vaccination due to the risk of Reye syndrome 1, 2
• Measles and varicella immunizations should be deferred for 11 months after high-dose IVIG administration 1, 2
• IVIG administration can occasionally be associated with increased blood viscosity and potential thromboembolism, requiring careful monitoring 6
• Incomplete Kawasaki disease (fewer than 4 classic criteria) should still be treated with standard IVIG and aspirin if there is evidence of coronary artery abnormalities or persistent inflammation 1, 2